Electrocatalytic water oxidation activity of phenolate-bridged dinuclear copper(ii) complexes in alkaline phosphate buffer

Abstract

Electrocatalytic oxidation of water by transition metal complexes to produce clean and renewable hydrogen fuel is a promising pathway for sustainable development. Herein, we reported the electrocatalytic water oxidation activity of two dinuclear copper(II) complexes, 1 ([Cu₂(L₁)₂(H₂O)₂]²⁺, [L₁H = methyl-2-(2-hydroxybenzylamino)-3-(1H-imidazol-4-yl)propanoate]) and 2 ([Cu₂(L₂)₂(H₂O)₂]²⁺, [L₂H = 2-((2-(pyridin-2-yl)ethylamino)methyl)phenol]), in basic phosphate buffer at pH 12. Complexes 1 and 2 showed stable and efficient catalytic activity, exhibiting turnover frequencies (TOFs) of 2.83 s⁻¹ and 28.87 s⁻¹ at overpotentials of approximately 365 mV and 345 mV, respectively, with ∼94% faradaic efficiency.